The piece of skull, taken from the right side of Horn's head, was then stored in his abdomen, Hammargren said.

The doctor said it was not clear when Horn will undergo the surgery to return the skull portion. Horn remains in critical but stable condition at University Medical Center.

Hammargren didn't perform Horn's surgery, but said he has talked extensively with Horn's surgeon, Dr. Derek Duke, about his treatment.

Hammargren previously has refused to disclose any details regarding Horn's treatment. He agreed to provide some specifics to correct misinformation reported by other media outlets.

"Dr. Duke did exactly the operation he should have. Otherwise, Roy would be dead," he said.

A portion of the skull is often removed following brain surgery, trauma, stroke or other medical problems that cause the brain to swell. Removing the skull allows the brain to expand.

The removed portion of the skull can then be stored either in a pouch in the abdomen or even in a freezer for safekeeping until it can be replaced, said Hammargren, a former Nevada lieutenant governor.

"I've been told Roy's skull has been put in a pouch in his abdomen," he said.

The New York Daily News, citing an unnamed source quoted in a tabloid newspaper, reported Wednesday that Horn underwent a "radical procedure called a hemicraniectomy on Oct. 4."

Hammargren said the procedure performed on Horn was not radical, nor was it a hemicraniectomy, which involves removing half of the skull.

Doctors instead performed a large decompressive craniectomy, which involves removing only one-quarter of the skull, Hammargren said.

Hammargren said he's been performing about one craniectomy a year for the past 30 years.

"He didn't have that big of an operation," Hammargren said, referring to the hemicraniectomy. "That means the whole side of his head would have been taken off. It has a very poor prognosis. Roy had half the size of a hemicraniectomy and it is not a radical operation."

The 59-year-old entertainer also suffered paralysis on his left side following the attack.

Hammargren said such paralysis can be temporary, but it's hard to determine Horn's prognosis at this point.

"Paralysis can get better after, but he had a pretty big stroke," he said. "We just don't know yet. Fortunately, the stroke didn't hit on the side where he talks, thinks and remembers. He can still comprehend things and do things."

It's Better that part of his head ended up in his abdomen rather than the tigers.

That sucks about his stroke, though. I hope when he gets out of his coma that he goes back and gets medieval on the tiger. Endagered species or not, if that tiger did that to me, there would be a lot of exta cute fuzzy white Exxon stuffed tigers on the market.